The present invention relates to a method of assembling body panels such as doors, an engine hood, a trunk lid, etc. and an automotive body together in an automobile production line such as an automobile coating line, the method essentially comprising temporarily removing the body panels from the automotive body, thereafter coating or otherwise treating the automotive body and the body panels, and then installing the body panels to the automotive body. The present invention is also directed to an apparatus for removing body panels from and installing body panels on an automotive body in the assembling method, and also a feed jig for holding and feeding body panels when they are removed from or installed on an automotive body, or treating body panels in the assembling method.
Automobile production lines include a section where an automotive body and various body panels such as doors, an engine hood, a trunk lid, etc. are coated or otherwise treated. To treat the automotive body and body panels in such a section, the body panels are temporarily removed from the automotive body. Then, the separated automotive body and body panels are coated or otherwise treated, and thereafter the body panels are installed back on the automotive body, i.e., they are assembled together.
In an automobile coating line, for example, it would be difficult to apply a uniform coating to body panels and an automotive body if the body panels remained attached to the automotive body. There has been known an assembling method which avoids the above drawback. According to the known assembling method, an automotive body and a body panel which is attached to the automotive body are pretreated, e.g., coated with an electrodeposited coating layer, and then the body panel is removed from the automotive body. The body panel and the automotive body are then fed along respective feed paths, during which an undercoat such as a surfacer and a sealing layer are applied to them. Thereafter, the body panel is installed again on the automotive body. In this manner, the automotive body and the body panel are coated and assembled together.
The body panel is removed from and installed on the automotive body in the following manner: Usually, there are employed a automotive body feed path for feeding the automotive body therealong, and a body panel feed path for feeding a feed jig on which the body panel can removably be mounted, the feed paths extending parallel to each other. Between these feed paths, there are disposed an apparatus for removing the body panel from the automotive body, and an apparatus for installing the body panel on the automotive body. For removal and installation of the body panel, the body panel is transferred between the automotive body fed along the automotive body feed path and the feed jig fed along the body panel feed path by the removing and installing apparatus. For example, Japanese Laid-Open Patent Publication No. 61(1986)-146690 discloses an apparatus for installing a door on an automotive body. The door installing apparatus is disposed between a door feed path for feeding a feed jig with the door removably mounted thereon and an automotive body feed path for feeding the automotive body. The door is detached from the feed jig and installed on the automotive body by the door installing apparatus.
Since the body panel feed path and the automotive body feed path are separately required for removal of the body panel from and installation of the body panel on the automotive body, the arrangement of the automobile coating line is large in size, and the range in which the body panel removing and installing apparatus operates is large. It is therefore time-consuming to install and remove the body panel, and the efficiency of the installing and removing process is poor. As the body panel removing and installing apparatus operates in a large range, the apparatus itself is large in size and complex in construction.
The body panel, which is installed on the automotive body by fasteners such as hinge pins or bolts, is normally held on the feed jig by a clamp or the like disposed on the feed jig. Consequently, when the body panel is detached from the automotive body and mounted on the feed jig, such fasteners are removed and not used, but when the body panel is to be installed back on the automotive body, the fasteners are required. It is therefore necessary to add a fastener feed path for feeding the removed fasteners from the area where the body panel is detached from the automotive body to the area where the body panel is attached again to the automotive body. As a result, the fasteners must be transferred between the body panel removing and installing apparatus and the fastener feed path. The additional fastener feed path and the transfer of the fasteners are obstacles to efforts to reduce the size of the automobile coating line, and also to increase the efficiency of removing and installing the body panel.
When each of body panels removed from an automotive body is to be coated in an automobile coating line, the body panel is horizontally or vertically mounted on a feed jig so that the surface of the body panel to be coated is directed laterally or upwardly, and is fed together with the feed jig while at the same time the surface of the body panel is coated by a coating robot, a reciprocator, or the like, as disclosed in Japanese Laid-Open Patent Publications Nos. 63(1988)-107782 and 59(1984)-98773.
According to the disclosed coating methods, the body panel is kept on the feed jig in a constant posture. For coating both inner and outer surfaces of the body panel, therefore, it is necessary to apply a coating to the inner surface, for example, of the body panel while the body panel is being supported on the feed path with the inner surface being directed upwardly or laterally, and then to mount the body panel again on the feed jig so that the outer surface of the body panel is upwardly or laterally. With the disclosed coating methods, therefore, it was difficult to successively coat the inner and outer surfaces efficiently while the body panel is being held on the feed jig.
After the body panel is coated, it is delivered, together with the feed jig, into a drying furnace in which the coated layer is baked. One problem is that since the coated surface is oriented upwardly or laterally, dust particles or other foreign matter may be applied to the coated surface, impairing the coated layer.
The feed jig disclosed in Japanese Laid-Open Patent Publications Nos. 63(1988)-107782 and 59(1984)-98773 is not so shaped as to take into account the transfer of a body panel between the feed jig and an automotive body. As a result, the operation of the body panel removing and installing apparatus is complex, lowering the efficiency in removing and installing the body panel.